Plating apparatus

ABSTRACT

A plating apparatus for use in forming a plated film in trenches, via holes, or resist openings that are defined in a surface of a semiconductor wafer, and forming bumps to be electrically connected to electrodes of a package, on a surface of a semiconductor wafer. The plating apparatus has a plating tank for holding a plating solution, a holder for holding a workpiece and bringing a surface to be plated of the workpiece into contact with the plating solution in the plating tank, and a ring-shaped nozzle pipe disposed in the plating tank and having a plurality of plating solution injection nozzles for injecting the plating solution to the surface to be plated of the workpiece held by the holder to supply the plating solution into the plating tank.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a plating apparatus for plating asurface (a surface to be plated) of a substrate or the like, and moreparticularly to a plating apparatus for use in forming a metal film andinterconnects on a substrate for LSI circuits or the like according toplating technology, forming a plated film in fine interconnect grooves(trenches), via holes, or resist openings that are defined in a surfaceof a semiconductor wafer or the like, and forming bumps (protrudingelectrodes) to be electrically connected to electrodes of a package orthe like, on a surface of a semiconductor wafer.

2. Background Art

In recent years, a method of forming interconnects or bumps insemiconductor circuits by forming metallic films on silicon wafers orother substrates according to plating technology has been employed.

In TAB (Tape Automated Bonding) or FC (Flip Chip), for example, it haswidely been practiced to form protruding connecting electrodes (bumps)of gold, copper, solder, lead-free solder, or nickel, or a multi-layerlaminate of these metals at predetermined portions (electrodes) on asurface of a semiconductor chip having interconnects formed therein, andto electrically connect the interconnects via the bumps with electrodesof a package or TAB electrodes. Methods of forming bumps include variousmethods, such as electroplating, vapor deposition, printing, and ballbumping. With a recent increase in the number of I/O in a semiconductorchip and a trend toward finer pitches, electroplating has morefrequently been employed because it can cope with fine processing andhas relatively stable performance.

In particular, metallic films produced by electroplating areadvantageous in that they are highly pure, can be grown at high speeds,and have their thicknesses easily controlled. Electroless plating, onthe other hand, is advantageous in that the number of steps required toform interconnects or bumps may be small as a seed layer for passing acurrent on a workpiece to be plated such as a substrate or the like isnot required. Since a film formed on a semiconductor substrate isstrictly required to be of uniform thickness, many attempts have beenmade to meet such a requirement in the above plating processes.

FIG. 27 shows an example of a conventional electroless plating apparatuswhich employs a so-called face-down method. The electroless platingapparatus has an upwardly opened plating tank 12 for holding a platingsolution (electroless plating solution) 10 therein, and a verticallymovable substrate holder 14 for detachably holding a substrate W as aworkpiece to be plated in a state such that a front face (surface to beplated) of the substrate W faces downward (face-down). An overflow tank16 is provided around an upper portion of the plating tank 12, and aplating solution discharge line 18 is connected to the overflow tank 16.Further, a plating solution supply nozzle 22 is provided at the bottomof the plating tank 12 and connected to the plating solution supply line20.

In operation, a substrate W held horizontally by the substrate holder 14is located at a position such as to close an opening at an upper end ofthe plating tank 12. In this state, the plating solution 10 is suppliedfrom the plating solution supply nozzle 22 into the plating solutiontank 12 and allowed to overflow the upper portion of the plating tank12, thereby flowing the plating solution 10 along a surface of thesubstrate W held by the substrate holder 14, and returning to acirculation tank (not shown) through the plating solution discharge line18. Thus, by bringing the plating solution into contact with apretreated surface of the substrate W, metal is deposited on the surfaceof the substrate W so as to form a metal film.

According to the plating apparatus, uniformity of the thickness of themetal film formed on the surface of the substrate W can be adjusted to acertain extent by adjusting the supply rate of the plating solution 10supplied from the plating solution supply nozzle 22, and rotating thesubstrate holder 14, and the like.

FIG. 28 shows an example of a conventional electroplating apparatuswhich employs a so-called dipping method. The electroplating apparatushas a plating tank 12 a for holding a plating solution (electroplatingsolution) therein, and a vertically movable substrate holder 14 a fordetachably holding a substrate W in a state such that a front face(surface to be plated) is exposed while a peripheral portion of thesubstrate W is water-tightly sealed. An anode 24 is held by an anodeholder 26 and disposed vertically within the plating tank 12 a. Further,a regulation plate 28 made of a dielectric material having a centralhole 28 a is disposed in the plating tank 12 a so as to be positionedbetween the anode 24 and the substrate W when the substrate W held bythe substrate holder 14 a is disposed at a position facing the anode 24.

In operation, the anode 24, the substrate W, and the regulation plate 28are immersed in the plating solution in the plating tank 12 a.Simultaneously, the anode 24 is connected via a conductor 30 a to ananode of a plating power supply 32, and the substrate W is connected viaa conductor 30 b to a cathode of the plating power supply 32. Thus, dueto a potential difference between the substrate W and the anode 24,metal ions in the plating solution receive electrons from the surface ofthe substrate W, so that metal is deposited on the surface of thesubstrate W so as to form a metal film.

According to the plating apparatus, the variation of the thickness ofthe metal film formed on the surface of the substrate W can be adjustedto a certain extent by disposing the regulation plate 28 having thecentral hole 28 a between the anode 24 and the substrate W disposed at aposition facing the anode 24, and adjusting a potential distribution onthe plating tank 12 a with the regulation plate 28.

FIG. 29 shows another example of a conventional electroplating apparatuswhich employs a so-called dipping method. The electroplating apparatusdiffers from the electroplating apparatus shown in FIG. 28 in that aring-shaped dummy cathode (dummy electrode) 34 is provided instead of aregulation plate, that a substrate W is held by a substrate holder 14 ain a state such that the dummy cathode 34 is disposed around thesubstrate W, and that the dummy cathode 34 is connected via a conductor30 c to a cathode of a plating power supply 32 during plating.

According to the plating apparatus, uniformity of thickness of a platedfilm formed on the surface of the substrate W can be improved byadjusting an electric potential of the dummy cathode 34.

FIG. 30 shows still another conventional electroplating apparatus whichemploys a so-called dipping method. The electroplating apparatus differsfrom the electroplating apparatus shown in FIG. 28 in that there is noregulation plate, a paddle shaft (stirring mechanism) 36 is positionedabove a plating tank 12 a and disposed parallel to and between asubstrate holder 14 a and an anode 24, and a plurality of paddles(stirring rods) 38 are suspended substantially vertically as stirringvanes from a lower surface of the paddle shaft 36, the arrangement beingsuch that, during a plating process, the paddle shaft 36 reciprocallymoves the paddles 38 parallel to a substrate W, thereby stirring aplating solution in the plating tank 12 a.

According to the plating apparatus, the paddle shaft 36 reciprocallymoves the paddles 38 parallel to the substrate W to uniformize flows ofthe plating solution (i.e., to eliminate the directivity of flows of theplating solution) along the surface of the substrate W over the entiresurface of the substrate W for thereby forming a plated film of moreuniform thickness over the entire surface of the substrate W.

For forming a metal film (plated film) as interconnects or bumps on asurface of a semiconductor substrate (wafer), for example, the surfaceconfiguration and film thickness of the metal film formed over theentire surface of the substrate are required to be uniform. While highlydense packaging technologies such as SOC, WL-CSP, etc. available inrecent years require more highly accurate uniformity, it would be highlydifficult for the conventional plating apparatus to produce a metal filmthat meets the requirements for such highly accurate uniformity.

Specifically, each of the conventional plating apparatuses has its ownstructural features that result in the film thickness variationcharacteristics of a plated film formed thereby, and to produce a platedfilm having better film thickness uniformity, improvement of the platingapparatus is required. For producing a plated film of uniform filmthickness, it is effective to uniformize flows of the plating solutionnear a surface to be plated of a substrate or the like. There is ademand for a process of making a uniform flow of plating solution andbringing the plating solution into contact with a surface to be platedof a substrate or the like. Plating apparatus themselves are alsorequired to have a simple structure and mechanism designed for easymaintenance. For example, the plating apparatus shown in FIG. 29 needsto be operated so as to adjust a dummy electrode and remove plated metalthat has been deposited on the dummy electrode. It has been desired tohandle the plating apparatus better and manage the plating apparatussimply and without the problems of operation and managementcomplexities. For shortening the plating time, it is very desirable toincrease the plating speed. Increasing the plating speed requiressupplying metal ions in the plating solution efficiently to a surface tobe plated of a substrate or the like.

In electroplating, one approach to increase the plating speed would beto increase the current density. However, simply increasing the currentdensity would cause burnt deposits, plating defects, passivation of theanode surface, etc., possibly resulting in plating failures.

BRIEF SUMMARY OF THE INVENTION

The present invention has been made in view of the above drawbacks. Itis, therefore, a first object of the present invention to provide aplating apparatus which is capable of increasing the plating speed andadjusting flows of a plating solution more uniformly in a plating tankto achieve higher within-wafer uniformity of the film thickness of aplated film with a relatively simple arrangement.

It is a second object of the present invention to provide a platingapparatus which is capable of forming a plated film having better filmthickness uniformity on a surface to be plated of a workpiece with arelatively simple arrangement and without needs for a complicatedoperation and setting.

To achieve the above objects, a plating apparatus, comprising: a platingtank for holding a plating solution is provided a holder for holding aworkpiece and bringing a surface to be plated of the workpiece intocontact with the plating solution in the plating tank, and a ring-shapednozzle pipe disposed in the plating tank and having a plurality ofplating solution injection nozzles for injecting the plating solutiontoward the surface to be plated of the workpiece held by the holder tosupply the plating solution into the plating tank.

According to the present invention, the plating solution is injectedfrom the plating solution injection nozzles formed on the ring-shapednozzle pipe and applied as strong streams to the surface to be plated ofthe workpiece, thereby efficiently supplying ions in the platingsolution to the surface to be plated of the workpiece while preventingthe uniformity of the potential distribution on the entire surface to beplated of the workpiece from being disturbed. The plating speed is thusincreased without degrading the quality of the plated film. In addition,the uniformity of the film thickness of the plated film can be increasedby adjusting the flow rate and direction of the plating solutioninjected from the plating solution injection nozzles in order to providea more uniform flow of the plating solution near the surface to beplated of the workpiece.

Streams of the plating solution injected from the plating solutioninjection nozzles should preferably join each other on or in front of asubstantially central area of the surface to be plated of the workpieceheld by the holder.

Since the joined flow of the plating solution is applied perpendicularlyto the substantially central area of the surface to be plated of theworkpiece, and thereafter changes its direction to spread outwardlyalong the surface to be plated of the workpiece, the flow of the platingsolution after it has impinged upon the surface to be plated of theworkpiece is prevented from interfering with a discharged flow of theplating solution, and hence is formed as a constant continuous andstable flow.

The plating apparatus may comprise an electroplating apparatus having ananode, and a plating voltage may be applied between the anode and theworkpiece to perform electroplating on the workpiece.

If the plating apparatus comprises an electroplating apparatus having ananode, then the plating apparatus should preferably further comprise aplating solution injection nozzle for injecting the plating solutiontoward the anode to supply the plating solution into the plating tank.

The rate at which the anode is dissolved is increased to make itpossible to dissolve the anode at a rate commensurate with an increasein the electroplating speed.

The plating apparatus may comprise an electroless plating apparatus forbringing an electroless plating solution into contact with the surfaceto be plated of the workpiece to perform electroless plating on theworkpiece.

The workpiece may be disposed horizontally or vertically.

The nozzle pipe may be shaped to extend along an outer profile of theworkpiece. For example, if the workpiece has a circular outer profile,then the nozzle pipe should comprise a circular ring-shaped nozzle pipe.If the workpiece has a rectangular outer profile, then the nozzle pipeshould comprise a rectangular ring-shaped nozzle pipe.

The nozzle pipe should preferably be movable relative to the workpieceheld by the holder. With this arrangement, the nozzle pipe may be movedin forward and backward directions, leftward and rightward directions,or upward and downward directions, or in a combination of thesedirections, with respect to the surface to be plated of the workpiece,or may be moved in a circular pattern in a plane parallel to the surfaceto be plated of the workpiece, or the nozzle pipe may make a swivelingmotion, for further increasing the uniformity of the film thickness ofthe plated film.

The nozzle pipe and/or the plating solution injection nozzles shouldpreferably be made of an electrically insulating material. The nozzlepipe and/or the plating solution injection nozzles which are made of anelectrically insulating material are effective to prevent the electricfield distribution in the plating tank from being disturbed thereby.

According to the present invention, there is also provided a platingapparatus, comprising: a plating tank for holding a plating solution;and a stirring mechanism having a stirring vane immersed in the platingsolution in the plating tank and disposed in a position facing a surfaceto be plated of a workpiece, the stirring vane being reciprocallymovable parallel to the surface to be plated of the workpiece to stirthe plating solution; wherein the stirring vane has irregularities on atleast one side thereof.

According to the above arrangement, the stirring vane with theirregularities on at least one side thereof is capable of generatingmany swirls uniformly and generally in the plating solution when thestirring vane is reciprocally moved. Thus, the flow of the platingsolution that is in contact with the surface to be plated of theworkpiece is more uniformly and effectively applied to form a platedfilm having better film thickness uniformity on the surface to be platedof the workpiece.

The irregularities comprise, for example, a succession of triangular orrectangular saw-tooth irregularities or a number of narrow groovesdefined at predetermined intervals.

Since the irregularities comprise a succession of triangular orrectangular saw-tooth irregularities or a number of narrow groovesdefined at predetermined intervals, many swirls are produced uniformlyand generally in the plating solution when the stirring vane isreciprocally moved. Thus, the flow of the plating solution that is incontact with the surface to be plated of the workpiece is more uniformlyand effectively applied to form a plated film having better filmthickness uniformity on the surface to be plated of the workpiece.

Preferably, the side of the stirring vane with the irregularitiesprovided thereon faces the surface to be plated of the workpiece.

Inasmuch as the side of the stirring vane with the irregularitiesprovided thereon faces the surface to be plated of the workpiece, manyswirls are produced uniformly and generally in the plating solution whenthe stirring vane is reciprocally moved. Thus, the flow of the platingsolution that is in contact with the surface to be plated of theworkpiece is more uniformly and effectively applied to form a platedfilm having better film thickness uniformity on the surface to be platedof the workpiece.

The stirring mechanism should preferably have a plurality of thestirring vanes.

If the stirring mechanism has a plurality of the stirring vanes, thenmore swirls are produced uniformly and generally in the plating solutionnear the surface to be plated of the workpiece when the stirring vane isreciprocally moved. Thus, the flow of the plating solution that is incontact with the surface to be plated of the workpiece is more uniformlyand effectively applied to form a plated film having better filmthickness uniformity on the surface to be plated of the workpiece.

According to the present invention, there is further provided a platingapparatus, comprising: a plating tank for holding a plating solution;and a stirring mechanism having a stirring vane immersed in the platingsolution in the plating tank for stirring the plating solution; whereinthe stirring vane comprises a plurality of stirring vanes which areactuatable by respective independent drive mechanisms.

According to the above arrangement, since the stirring vane comprises aplurality of stirring vanes having respective independent drivemechanisms, the stirring distribution of the plating solution can beadjusted to form a plated film having better film thickness uniformityon the surface to be plated of the workpiece.

Preferably, the stirring vanes are different in shape from each other.

Since the stirring vanes of the stirring mechanisms are different inshape from each other, the stirring distribution of the plating solutioncan be adjusted to form a plated film having better film thicknessuniformity on the surface to be plated of the workpiece.

Preferably, the stirring vanes are reciprocally movable in directionsparallel to a surface to be plated of a workpiece.

Because the stirring vanes are reciprocally movable in directionsparallel to a surface to be plated of a workpiece, the stirringdistribution of the plating solution can be adjusted to form a platedfilm having better film thickness uniformity on the surface to be platedof the workpiece.

According to the present invention, there is also provided a platingapparatus, comprising: a plating tank for holding a plating solution;and a stirring mechanism having a stirring vane immersed in the platingsolution in the plating tank and disposed in a position facing a surfaceto be plated of a workpiece, the stirring vane being reciprocallymovable parallel to the surface to be plated of the workpiece to stirthe plating solution; wherein the stirring vane has an angle withrespect to the surface to be plated of the workpiece, the angle beingvariable as the direction in which the stirring vane moves is changed.

According to the above arrangement, the angle of the stirring vane withrespect to the surface to be plated of the workpiece is changed as thedirection in which the stirring vanes moves is changed, thus producing aflow of the plating solution uniformly and generally. Thus, the flow ofthe plating solution that is in contact with the surface to be plated ofthe workpiece is more uniformly and effectively applied to form a platedfilm having better film thickness uniformity on the surface to be platedof the workpiece.

The stirring mechanism should preferably have a plurality of thestirring vanes.

With the plural stirring vanes used, a flow of the plating solution isproduced uniformly and generally when the stirring vanes arereciprocally moved. Thus, the flow of the plating solution that is incontact with the surface to be plated of the workpiece is more uniformlyand effectively applied to form a plated film having better filmthickness uniformity on the surface to be plated of the workpiece.

According to the present invention, there is also provided a platingapparatus, comprising: a plating tank for holding a plating solution; ananode immersed in the plating solution in the plating tank and disposedin a position facing a surface to be plated of a workpiece; and astirring mechanism for stirring the plating solution in the platingtank; wherein the stirring mechanism has a first stirring vane disposedclosely to the surface to be plated of the workpiece and a secondstirring vane disposed closely to the anode.

According to the above arrangement, the stirring mechanism has the firststirring vane disposed close to the surface to be plated of theworkpiece and the second stirring vane disposed close to the anode. Whenthe first and second stirring vanes are moved, a flow of the platingsolution is produced close to the surface to be plated of the workpieceand the anode. The flow of the plating solution that is in contact withthe surface to be plated of the workpiece is more uniformly andeffectively applied to form a plated film having better film thicknessuniformity on the surface to be plated of the workpiece.

Preferably, the first stirring vane is reciprocally movable parallel tothe surface to be plated of the workpiece, and the second stirring vaneis reciprocally movable parallel to a surface of the anode which facesthe surface to be plated of the workpiece.

When the first stirring vane is reciprocally moved parallel to thesurface to be plated of the workpiece, and the second stirring vane isreciprocally moved parallel to a surface of the anode which faces thesurface to be plated of the workpiece, a flow of the plating solution isproduced close to the surface to be plated of the workpiece and theanode. The flow of the plating solution that is in contact with thesurface to be plated of the workpiece is more uniformly and effectivelyapplied to form a plated film having better film thickness uniformity onthe surface to be plated of the workpiece.

The above and other objects, features, and advantages of the presentinvention will be apparent from the following description when taken inconjunction with the accompanying drawings which illustrates preferredembodiments of the present invention by way of example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of the overall layout of a plating facility having aplating apparatus (electroplating apparatus) according to an embodimentof the present invention;

FIG. 2 is a schematic view of a transfer robot disposed in a platingspace in the plating facility shown in FIG. 1;

FIG. 3 is a cross-sectional view of the plating apparatus(electroplating apparatus) provided in the plating facility shown inFIG. 1;

FIG. 4 is a perspective view of a fixing plate and a nozzle pipe of theplating apparatus shown in FIG. 3;

FIGS. 5A through 5E are cross-sectional diagrams sequentiallyillustrating a process of forming a bump (protruding electrode) on asubstrate;

FIG. 6 is a schematic cross-sectional view of a plating apparatus(electroplating apparatus) according to another embodiment of thepresent invention;

FIG. 7 is a schematic cross-sectional view of a plating apparatus(electroplating apparatus) according to still another embodiment of thepresent invention;

FIG. 8 is a schematic cross-sectional view of a plating apparatus(electroplating apparatus) according to yet another embodiment of thepresent invention;

FIG. 9 is a view showing an example of motion (swiveling motion) of anozzle pipe;

FIG. 10 is a schematic cross-sectional view of a plating apparatus(electroless plating apparatus) according to yet another embodiment ofthe present invention;

FIG. 11 is a plan view of a nozzle pipe of the plating apparatus shownin FIG. 10;

FIG. 12 is a right-hand side view of the nozzle pipe shown in FIG. 11;

FIG. 13 is a plan view of a modification of the nozzle pipe;

FIG. 14 is a schematic cross-sectional view of a plating apparatus(electroplating apparatus) according to yet another embodiment of thepresent invention;

FIG. 15 is a plan view of another modification of the nozzle pipe;

FIG. 16 is a schematic perspective view of a plating apparatus(electroplating apparatus) according to yet another embodiment of thepresent invention;

FIGS. 17A through 17C are views showing different shapes of stirringvanes, respectively;

FIG. 18 is a schematic perspective view of a plating apparatus(electroplating apparatus) according to a yet another embodiment of thepresent invention;

FIG. 19A is a plan view of another stirring mechanism;

FIG. 19B is a front view of another stirring mechanism;

FIG. 20A is a side view of still another stirring mechanism;

FIG. 20B is a front view of the still another stirring mechanism;

FIG. 21A is a side view of yet another stirring mechanism;

FIG. 21B is a front view of the yet another stirring mechanism;

FIG. 22 is a perspective view of yet another stirring vane;

FIG. 23 is a view showing the relationship between a direction of motionof the stirring vane shown in FIG. 22 and an angle of the stirring vanewith respect to a surface to be plated of a workpiece;

FIG. 24 is a view showing the relationship between another direction ofmotion of the stirring vane shown in FIG. 22 and an angle of thestirring vane with respect to a surface to be plated of a workpiece;

FIG. 25 is a schematic perspective view of a plating apparatus(electroplating apparatus) according to yet another embodiment of thepresent invention;

FIG. 26 is a schematic perspective view of a plating apparatus(electroplating apparatus) according to yet another embodiment of thepresent invention;

FIG. 27 is a schematic cross-sectional view of a conventional platingapparatus (electroless plating apparatus);

FIG. 28 is a schematic cross-sectional view of a conventional platingapparatus (electroplating apparatus);

FIG. 29 is a schematic cross-sectional view of another conventionalplating apparatus (electroplating apparatus); and

FIG. 30 is a schematic cross-sectional view of still anotherconventional plating apparatus (electroplating apparatus).

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be described below withreference to the drawings. The following embodiments show examples inwhich a substrate such as a semiconductor wafer is used as a workpieceto be plated.

FIG. 1 shows an overall layout of a plating facility having a platingapparatus according to an embodiment of the present invention. Theplating facility is designed so as to automatically perform all theplating processes including pretreatment of a substrate, plating, andafter treatment of the plating, in a successive manner. The interior ofan apparatus frame 110 having an armored panel attached thereto isdivided by a partition plate 112 into a plating space 116 for performinga plating process of a substrate and treatments of the substrate towhich a plating solution is attached, and a clean space 114 forperforming other processes, i.e. processes not directly involving aplating solution. Two substrate holders 160 (see FIG. 2) are arranged inparallel, and substrate attachment/detachment stages 162 to attach asubstrate to and detach a substrate from each substrate holder 160 areprovided as a substrate delivery section on a partition portionpartitioned by the partition plate 112, which divides the plating space116 from the clean space 114. Loading/unloading ports 120, on whichsubstrate cassettes housing substrates are mounted, are connected to theclean space 114. Further, the apparatus frame 110 has a console panel121 provided thereon.

In the clean space 114, there are disposed at four corners an aligner122 for aligning an orientation flat or a notch of a substrate with apredetermined direction, two cleaning/drying devices 124 for cleaning aplated substrate and rotating the substrate at a high speed to spin-drythe substrate, and a pretreatment device 126 for carrying out apretreatment of a substrate, e.g., according to the present embodiment,a rinsing pretreatment including injecting pure water toward a frontface (surface to be plated) of a substrate to thereby clean thesubstrate surface with pure water and, at the same time, wet thesubstrate surface with pure water so as to enhance a hydrophilicity ofthe substrate surface. Further, a first transfer robot 128 is disposedsubstantially at the center of these processing devices, i.e. thealigner 122, the cleaning/drying devices 124, and the pretreatmentdevice 126, to thereby transfer and deliver a substrate between theprocessing devices 122, 124, and 126, the substrateattachment/detachment stages 162, and the substrate cassettes mounted onthe loading/unloading ports 120.

The aligner 122, the cleaning/drying devices 124, and the pretreatmentdevice 126 disposed in the clean space 114 are designed so as to holdand process a substrate in a horizontal state in which a front face ofthe substrate faces upward. The transfer robot 128 is designed so as totransfer and deliver a substrate in a horizontal state in which a frontface of the substrate faces upward.

In the plating space 116, in the order from the partition plate 112side, there are disposed a stocker 164 for storing or temporarilystoring the substrate holders 160, an activation treatment device 166for etching, for example, an oxide film, having a large electricresistance, on a seed layer formed on a surface of a substrate with achemical liquid such as sulfuric acid or hydrochloric acid to remove theoxide film, a first rinsing device 168 a for rinsing the surface of thesubstrate with pure water, a plating apparatus 170 for carrying outplating, a second rinsing device 168 b, and a blowing device 172 fordewatering the plated substrate. Two second transfer robots 174 a and174 b are disposed beside these devices so as to be movable along a rail176. One of the second transfer robots 174 a transfers the substrateholders 160 between the substrate attachment/detachment stages 162 andthe stocker 164. The other of the second transfer robots 174 b transfersthe substrate holders 160 between the stocker 164, the activationtreatment device 166, the first rinsing device 168 a, the platingapparatus 170, the second rinsing device 168 b, and the blowing device172.

As shown in FIG. 2, each of the second transfer robots 174 a and 174 bhas a body 178 extending in a vertical direction and an arm 180 which isvertically movable along the body 178 and rotatable about its axis. Thearm 180 has two substrate holder retaining portions 182 provided inparallel for detachably retaining the substrate holders 160. Thesubstrate holder 160 is designed so as to hold a substrate W in a statesuch that a front face of the substrate is exposed while a peripheralportion of the substrate is sealed, and to be capable of attaching thesubstrate W to the substrate holder 160 and detaching the substrate Wfrom the substrate holder 160.

The stocker 164, the activation treatment device 166, the rinsingdevices 168 a, 168 b, and the plating apparatus 170 are designed so asto engage with outwardly projecting portions 160 a provided at both endsof each substrate holder 160 to thus support the substrate holders 160in a state such that the substrate holders 160 are suspended in avertical direction. The activation treatment device 166 has twoactivation treatment tanks 183 for holding a chemical liquid therein. Asshown in FIG. 2, the arm 180 of the second transfer robot 174 b holdingthe substrate holders 160, which are loaded with the substrates W, in avertical state is lowered so as to engage the substrate holders 160 withupper ends of the activation treatment tanks 183 to support thesubstrate holders 160 in a suspended manner as needed. Thus, theactivation treatment device 166 is designed so that the substrateholders 160 are immersed together with the substrates W in the chemicalliquid in the activation treatment tanks 183 to carry out an activationtreatment.

Similarly, the rinsing devices 168 a and 168 b have two rinsing tanks184 a and two rinsing tanks 184 b which hold pure water therein,respectively, and the plating apparatus 170 has a plurality of platingtanks 186 which hold a plating solution therein. The rinsing devices 168a, 168 b and the plating apparatus 170 are designed so that thesubstrate holders 160 are immersed together with the substrates W in thepure water in the rinsing tanks 184 a, 184 b or the plating solution inthe plating tanks 186 to carry out rinsing treatment or plating in thesame manner as described above. The arm 180 of the second transfer robot174 b holding the substrate holders 160 with substrates W in a verticalstate is lowered, and air or inert gas is injected toward the substratesW mounted on the substrate holders 160 to blow away a liquid attached tothe substrate holders 160 and the substrates W and to dewater thesubstrates W. Thus, the blowing device 172 is designed so as to carryout blowing treatment.

As shown in FIG. 3, each plating tank 186 in the plating apparatus 170is designed so as to hold a plating solution 188 therein. Thus, thesubstrates W, which are held in a state such that the front faces(surfaces to be plated) are exposed while peripheral portions of thesubstrates W are water-tightly sealed with the substrate holders 160,are immersed in the plating solution 188.

An overflow tank 202 is provided at a side of the plating tank 186 forreceiving a plating solution 188 overflowing upper end of overflow weir200 of the plating tank 186. A plating solution discharge line 204 isconnected to the overflow tank 202. A plating liquid circulation line208 connecting between the plating solution discharge line 204 and abelow-described plating liquid supply line 218 has a circulating pump208, a flow rate adjusting unit 210, and a filter 212 therein. A platingsolution 188 supplied into the plating tank 186 by operation of thecirculating pump 208 fills the plating tank 186, then overflows theoverflow weir 200, flows into the overflow tank 202, and returns to thecirculating pump 208. Thus, the plating solution 188 is circulated andthe flow rate of the plating solution flowing along the plating liquidcirculation line 208 is adjusted by the flow rate adjusting unit 210.

An anode 214 in the form of a disk shaped like a substrate W is held byan anode holder 216 and vertically disposed in the plating tank 186.When the plating tank 186 is filled with the plating solution 188, theanode 216 is immersed in the plating solution 188 and faces a substrateW held by the substrate holder 160, and placed in a predeterminedposition in the plating tank 186.

In the plating tank 186, there is also disposed a ring-shaped nozzlepipe 220 positioned between the anode 214 and the substrate holder 160that is placed at the predetermined position in the plating tank 186.The nozzle pipe 220 is connected to a plating solution supply line 218.As shown in FIG. 4, the nozzle pipe 220 is shaped as a circular ringalong the outer profile of the substrate W, and has a plurality ofplating solution injection nozzles 222 located at a predetermined pitchin respective predetermined positions spaced in the circumferentialdirection of the nozzle pipe 220. The plating solution 188, which iscirculated by operation of the circulation pump 208, as described above,is injected from the plating solution injection nozzles 222 and suppliedinto the plating tank 186.

In this embodiment, the nozzle pipe 220 is fixed by fasteners 226 to arectangular fixing plate 224 which has an opening 224 a defined thereinand divides the interior of the plating tank 186 into a compartment forhousing the anode 214 therein and a compartment for housing thesubstrate W therein. The opening 224 a has a size which is substantiallythe same as, or slightly smaller than, the inside diameter of the nozzlepipe 220. The nozzle pipe 220 is positioned on the substrate side of thefixing plate 224 and disposed in surrounding relation to the surroundingedge of the opening 224 a. The plating solution injection nozzles 222are oriented such that the streams of the plating solution 188 injectedfrom the plating solution injection nozzles 222 join each other at ajoint point P which is in front of a substantially central area of thesubstrate W held by the substrate holder 160, and disposed in thepredetermined position in the plating tank 186.

The plating solution injection nozzles 222 formed on the ring-shapednozzle pipe 220 inject the plating solution 188 to supply the platingsolution 188 into the plating tank 186 and circulate the platingsolution 188. At this time, the plating solution 188 injected from theplating solution injection nozzles 222 is applied as strong streams tothe surface (surface to be plated) of the substrate W, therebyefficiently supplying ions in the plating solution 188 to the surface ofthe substrate W while preventing the uniformity of the potentialdistribution on the entire surface of the substrate W from beingdisturbed. The plating speed is thus increased without degrading thequality of the plated film. In addition, the uniformity of the filmthickness of the plated film formed on the surface of the substrate Wcan be increased by adjusting the flow rate and direction of the platingsolution 188 injected from the plating solution injection nozzles 222 inorder to provide a more uniform flow of the plating solution 188 nearthe surface of the substrate W.

In particular, since the streams of the plating solution 188 injectedfrom the plating solution injection nozzles 222 join each other at thejoint point P which is in front of the substantially central area of thesurface of the substrate W, the flow of the plating solution 188 isapplied perpendicularly to the substantially central area of the surfaceof the substrate W. Thereafter, the flow of the plating solution 188changes its direction to spread outwardly along the surface of thesubstrate W. Therefore, the flow of the plating solution 188 after ithas impinged upon the surface of the substrate W is prevented frominterfering with the discharged flow of the plating solution 188, andhence is formed as a constant continuous and stable flow.

The nozzle pipe 220, the plating solution injection nozzles 222 and thefixing plate 224 should preferably be made of a dielectric material suchas PVC, PP, PEEK, PES, HT-PVC, PFA, PTFE, or other resin materials.These dielectric materials are effective to prevent the electric fielddistribution in the plating tank 186 from being disturbed.

The interior of the plating tank 186 is divided with the fixing plate224 having the opening 224 a. The plating solution 188 passes throughthe opening 224 a and thereafter flows into the overflow tank 202.Consequently, the potential distribution over the entire area of thesubstrate W is made more uniform.

The plating apparatus 170 operates as follows: First, the plating tank186 is filled with the plating solution 188. Then, the substrate holder160 which is holding the substrate W is lowered to place the substrate Win a predetermined position where the substrate W is immersed in theplating solution 188 in the plating tank 186. Then, the circulation pump208 is operated to inject the plating solution 188 from the platingsolution injection nozzles 222 toward the surface of the substrate W,thus supplying the plating solution 188 into the plating tank 186 andcirculating the plating solution 188. At the same time, the anode 214 isconnected via a conductor 228 a to an anode of a plating power supply230, and the substrate W is connected via a conductor 228 b to a cathodeof the plating power supply 230, thus precipitating metal on the surfaceof the substrate W to form a metal film thereon.

At this time, the plating solution 188 injected from the platingsolution injection nozzles 222 is applied as strong streams to thesurface (to be plated) of the substrate W, so that the plating speed canbe increased without degrading the quality of the plated film. Inaddition, the uniformity of the film thickness of the plated film formedon the surface of the substrate W can be increased by making adjustmentsto provide a more uniform flow of the plating solution 188 near thesurface of the substrate W.

After the plating process is finished, the plating power supply 230 isdisconnected from the substrate W and the anode 214, and the substrateholder 160 together with the substrate W is pulled upward. The substrateW is then processed, e.g., cleaned with water and rinsed, after whichthe plated substrate W is delivered to a next process.

A series of bump plating processes in the plating facility thusconstructed will be described below with reference to FIGS. 5A through5E. First, as shown in FIG. 5A, a seed layer 500 is deposited as afeeding layer on a surface of a substrate W, and a resist 502 having aheight H of, for example, about 20 to 120 μm is applied onto the entiresurface of the seed layer 500. Thereafter, an opening 502 a having adiameter D₁ of, for example, about 20 to 200 μm is formed at apredetermined position of the resist 502. Substrates W thus prepared arehoused in a substrate cassette in a state such that front faces(surfaces to be plated) of the substrates face upward. The substratecassette is mounted on the loading/unloading port 120.

One of the substrates W is taken out of the substrate cassette mountedon the loading/unloading port 120 by the first transfer robot 128 andplaced on the aligner 122 to align an orientation flat or a notch of thesubstrate with a predetermined direction. The substrate W thus alignedis transferred to the pretreatment device 126 by the first transferrobot 128. In the pretreatment device 126, a pretreatment (rinsingpretreatment) using pure water as a pretreatment liquid is carried out.On the other hand, two substrate holders 160 which have been stored in avertical state in the stocker 164 are taken out by the second transferrobot 174 a, rotated through 90° so that the substrate holders 160 arebrought into a horizontal state, and then placed in parallel on thesubstrate attachment/detachment stages 162.

Then, the substrates W which have been subjected to the aforementionedpretreatment (rinsing pretreatment) are loaded into the substrateholders 160 placed on the substrate attachment/detachment stages 162 ina state such that peripheral portions of the substrates W are sealed.The two substrate holders 160 which have been loaded with the substratesW are simultaneously retained, lifted, and then transferred to thestocker 164 by the second transfer robot 174 a. The substrate holders160 are rotated through 90° into a vertical state and lowered so thatthe two substrate holders 160 are held (temporarily stored) in thestocker 164 in a suspended manner. The above operation is carried outrepeatedly in a sequential manner, so that substrates are sequentiallyloaded into the substrate holders 160, which are stored in the stocker164, and are sequentially held (temporarily stored) in the stocker 164at predetermined positions in a suspended manner.

On the other hand, the two substrate holders 160 which have been loadedwith the substrates and temporarily stored in the stocker 164 aresimultaneously lifted, and then transferred to the activation treatmentdevice 166 by the second transfer robot 174 b. Each substrate isimmersed in a chemical liquid such as sulfuric acid or hydrochloric acidheld in the activation treatment tank 183 to thereby etch an oxide film,having a large electric resistance, formed on the surface of the seedlayer so as to expose a clean metal surface. The substrate holders 160which have been loaded with the substrates are transferred to the firstrinsing device 168 a in the same manner as described above to rinse thesurfaces of the substrates with pure water held in the rinsing tanks 184a.

The substrate holders 160 which have been loaded with the rinsedsubstrates are transferred to the plating apparatus 170 in the samemanner as described above. Each substrate W is supported in a suspendedmanner by the plating tank 186 in a state such that the substrate W isimmersed in the plating solution 188 held in the plating tank 186 tothus carry out plating on the surface of the substrate W. After apredetermined period of time has elapsed, the substrate holders 160which have been loaded with the substrates are pulled up from theplating tank 186 by the second transfer robot 174 b. Thus, the platingprocess is completed.

Thereafter, the substrate holders 160 are transferred to the secondrinsing device 168 b in the same manner as described above. Thesubstrate holders 160 are immersed in pure water in the rinsing tanks184 b to clean the surfaces of the substrates with pure water. Then, thesubstrate holders 160 which have been loaded with the substrates aretransferred to the blowing device 172 in the same manner as describedabove. In the blowing device 172, inert gas or air is injected towardthe substrates to blow away a plating solution and water dropletsattached to the substrates and the substrate holders 160. Thereafter,the substrate holders 160 which have been loaded with the substrates arereturned to predetermined positions in the stocker 164 and held in asuspended state in the same manner as described above.

The second transfer robot 174 b sequentially performs the aboveoperation repeatedly so that the substrate holders 160 which have beenloaded with the plated substrates are sequentially returned topredetermined positions in the stocker 164 and held in a suspendedmanner.

On the other hand, the two substrate holders 160 which have been loadedwith the plated substrates are simultaneously placed on the substrateattachment/detachment stages 162 by the second transfer robot 174 a inthe same manner as described above.

The first transfer robot 128 disposed in the clean space 114 takes thesubstrate out of the substrate holders 160 placed on the substrateattachment/detachment stages 162 and transfers the substrate to eitherone of the cleaning/drying devices 124. In the cleaning/drying device124, the substrate held in a horizontal state such that the front faceof the substrate faces upward is cleaned with pure water or the like androtated at a high speed to spin-dry the substrate. Thereafter, thesubstrate is then returned to the substrate cassette mounted on theloading/unloading port 120 by the first transfer robot 128. Thus, aseries of plating processes is completed. As a result, as shown in FIG.5B, a substrate W having a plated film 504 grown in the opening 502 aformed in the resist 502 can be obtained.

The spin-dried substrate W, as described above, is immersed in a solventsuch as acetone at a temperature of, for example, 50 to 60° C. to removethe resist 502 from the substrate W as shown in FIG. 5C. Further, asshown in FIG. 5D, an unnecessary seed layer 502, which is exposed afterplating, is removed. Next, the plated film 504 formed on the substrate Wis reflowed to form a bump 506 having a round shape due to surfacetension as shown in FIG. 5E. The substrate W is then annealed at atemperature of, for example, 100° C. or more to remove residual stressin the bump 506.

According to this embodiment, delivery of substrates in the platingspace 116 is performed by the second transfer robots 174 a, 174 bdisposed in the plating space 116, whereas delivery of substrates in theclean space 114 is performed by the first transfer robot 128 disposed inthe clean space 114. Accordingly, it is possible to improve thecleanliness around a substrate in the plating facility which performsall the plating processes including pretreatment of a substrate,plating, and after treatment of the plating, in a successive manner, andto increase a throughput of the plating facility. Further, it ispossible to reduce loads on facilities associated with the platingfacility and to achieve downsizing of the plating facility.

In the present embodiment, the plating apparatus 170 for performing theplating process has the plating tank 186 which is of a small footprint.Therefore, a plating apparatus 170 having a number of plating tanks 186may be small in size, making smaller facility loads ancillary to aplating plant. In FIG. 1, one of two cleaning/drying devices 124 may bereplaced with a pretreatment device.

FIG. 6 shows a plating apparatus (electroplating apparatus) according toanother embodiment of the present invention. The plating apparatus shownin FIG. 6 is different from the plating apparatus shown in FIGS. 3 and 4in that a regulation plate 232 having a central hole 232 a and athickness ranging from 0.5 to 10 mm and made of a dielectric materialsuch as PVC, PP, PEEK, PES, HT-PVC, PFFA, PTFE, or other resin materialsis disposed between the substrate holder 160 which holds the substrate Wand is disposed in a predetermined position in the plating tank 186 andthe nozzle pipe 220 which has the plating solution injection nozzles222. Other structural details of the plating apparatus shown in FIG. 6are identical to those of the plating apparatus shown in FIGS. 3 and 4.

In the present embodiment, the regulation plate 232 having the centralhole 232 a regulates the potential distribution in the plating tank 186to prevent the plating film grown on the peripheral edge of thesubstrate W from increasing in thickness.

FIG. 7 shows a plating apparatus (electroplating apparatus) according tostill another embodiment of the present invention. The plating apparatusshown in FIG. 7 is different from the plating apparatus shown in FIG. 6in that a stirring mechanism 236 having a stirring vane (paddle) 234 isdisposed between the substrate holder 160 which holds the substrate Wand is disposed in a predetermined position in the plating tank 186 andthe regulation plate 232. The stirring mechanism 236 reciprocally movesthe stirring vane 234 parallel to the substrate W held by the substrateholder 160 for thereby stirring the plating solution 188.

In the present embodiment, the stirring vane 234 is reciprocally movedparallel to the substrate W in the plating solution 188 by the stirringmechanism 236 to stir the plating solution 188 that is present betweenthe regulation plate 232 and the substrate W, thereby making moreuniform the flow of the plating solution 188 along the surface of thesubstrate W over the entire surface of the substrate W to form a platedfilm of more uniform film thickness over the entire surface of thesubstrate W.

In the present embodiment, the stirring vane 234 has irregularities 234a on its side facing the substrate W. The stirring vane 234 with theirregularities 234 a on its side facing the substrate W is capable ofgenerating many swirls uniformly and generally in the plating solution188 when the stirring vane 234 is reciprocally moved, as with abelow-described embodiment. Thus, the flow of the plating solution 188that is in contact with the surface (to be plated) of the substrate W ismore uniformly and effectively applied to form a plated film havingbetter film thickness uniformity, i.e., a plated film having a moreuniform film thickness, on the surface of the substrate W.

FIG. 8 shows a plating apparatus (electroplating apparatus) according toyet another embodiment of the present invention. The plating apparatusshown in FIG. 8 is different from the plating apparatus shown in FIG. 7in that the nozzle pipe 220 also has a plurality of plating solutioninjection nozzles 240 on its side facing the anode 214 for injecting theplating solution 188 toward the anode 214, thereby applying streams ofplating solution 188 injected from the plating solution injectionnozzles 240 to the anode 214. Since the injected streams of platingsolution 188 are also applied to the anode 214, the rate at which theanode 214 is dissolved is increased to make it possible to dissolve theanode 214 at a rate commensurate with an increase in the electroplatingspeed.

In the above embodiments, the nozzle pipe 220 is fixedly mounted in theplating tank 186 by the fixing plate 224. However, the nozzle pipe maybe moved in forward and backward directions, leftward and rightwarddirections, or upward and downward directions, or in a combination ofthese directions, with respect to the substrate W held by the substrateholder 160. The nozzle pipe may be moved in a circular pattern in aplane parallel to the surface of the substrate, or as shown in FIG. 9,the nozzle pipe 220 may make a swiveling motion. This makes it possibleto further increase the uniformity of the film thickness of the platedfilm. The same is true for each of embodiments to be described below.

FIGS. 10 through 12 show a plating apparatus according to yet stillanother embodiment of the present invention. According to the presentembodiment, the principles of the invention are applied to anelectroless plating apparatus for performing electroless plating on asurface (surface to be plated) of the substrate W which is held with thesurface facing downward.

The electroless plating apparatus has an upwardly opened plating tank302 for holding a plating solution (electroless plating solution) 300therein, and a vertically movable substrate holder 304 for detachablyholding the substrate W horizontally with the surface (surface to beplated) thereof facing downward. An overflow tank 306 is disposed aroundan upper portion of the plating tank 302, and connected to a platingsolution discharge line 308. A nozzle pipe 312 connected to a platingsolution supply line 310 is horizontally disposed in a position in theplating tank 302 where the nozzle pipe 312 is immersed in the platingsolution 300 held in the plating tank 302. The nozzle pipe 312 has aplurality of plating solution injection nozzles 314 located at apredetermined pitch in respective predetermined positions spaced in thecircumferential direction of the nozzle pipe 312. The plating solutiondischarge line 308 and the plating solution supply line 310 areconnected to each other with a plating solution circulation line, aswith the embodiments described above.

The plating solution injection nozzles 314 are oriented such that theyinject the plating solution 300 upwardly and inwardly (toward thecenter), and the streams of the plating solution 300 injected from theplating solution injection nozzles 314 join each other in front of asubstantially central area of the lower surface of the substrate W.

In the present embodiment, the plating solution 300 is injected from theplating solution injection nozzles 314 toward the substrate W that isheld by the substrate holder 304, disposed in a position to close theopening at the upper end of the plating tank 302, and rotated, ifnecessary, and is supplied into the plating tank 302 and circulated forperforming electroless plating. In the present embodiment, the platingsolution 300 injected from the plating solution injection nozzles 314 isapplied as strong streams to the surface (to be plated) of the substrateW, thereby increasing the plating speed without degrading the quality ofthe plated film. In addition, the uniformity of the film thickness ofthe plated film formed on the surface of the substrate W can beincreased by making adjustments to provide a more uniform flow of theplating solution 300 near the surface of the substrate W.

As shown in FIG. 13, segments 316 having respective plating solutioninjection nozzles 314 may be interconnected by joints 318 in aring-shaped pattern, thus providing a nozzle pipe 312. With thisarrangement, the nozzle pipe 312 can be fabricated conveniently. Thesame is true for the above embodiments and embodiments to be describedbelow.

FIG. 14 shows a plating apparatus according to yet another embodiment ofthe present invention. According to the present embodiment, theprinciples of the invention are applied to an electroplating apparatusfor performing electroplating on a surface (surface to be plated) of thesubstrate W which is held with the surface facing downward. The platingapparatus shown in FIG. 14 is different from the plating apparatus shownin FIGS. 10 through 12 in that an electroplating solution is used as theplating solution 300 and an anode 320 in the form of a flat plate isplaced on the bottom of the plating tank 302 below the nozzle pipe 312.The plating solution injection nozzles 314 inject the plating solution300 toward the surface of the substrate W to supply the plating solution300 into the plating tank 302 and circulate the plating solution 300. Atthe same time, the anode 320 is connected via a conductor 322 a to ananode of a plating power supply 324, and the substrate W is connectedvia a conductor 322 b to a cathode of the plating power supply 324, thusperforming a plating (electroplating) process.

In the above embodiments, the substrate W as a workpiece to be plated isof a circular shape, and the nozzle pipes 220, 312 are of a circularring shape extending along the outer profile of the substrate W. If arectangular substrate or the like is employed as a workpiece to beplated, then, as shown in FIG. 15, a nozzle pipe 342 having arectangular ring shape with plating solution injection nozzles 340disposed on respective four corners thereof and oriented in apredetermined direction may be employed. The nozzle pipe 342 is capableof forming a more uniform plating solution flow over the entire surfaceof the rectangular substrate.

According to the present invention, as described above, ions in theplating solution can efficiently be supplied to the surface (to beplated) of the substrate while preventing the uniformity of thepotential distribution on the surface of the substrate from beingdisturbed, so that the plating speed can be increased without degradingthe quality of the plated film. In addition, the uniformity of the filmthickness of the plated film can be increased by adjusting the flow rateand direction of the plating solution injected from the plating solutioninjection nozzles in order to provide a more uniform flow of the platingsolution near the surface to be plated.

FIG. 16 shows a plating apparatus (electroplating apparatus) accordingto yet another embodiment of the present invention. As shown in FIG. 16,a plating apparatus 610 has a plating tank 611 holding therein a platingsolution in which a substrate W held by a substrate holder 612 and ananode 615 held by an anode holder 614 are vertically disposed parallelto each other in confronting relation to each other. The substrate W isconnected via a conductor 616 to a cathode of a plating power supply617, and the anode 615 is connected via a conductor 618 to an anode ofthe plating power supply 617.

A stirring mechanism 620 having a stirring vane 619 for stirring theplating solution is disposed between the substrate W and the anode 615.The stirring vane 619 extends substantially vertically from the upperportion toward the bottom of the plating tank 611. The stirringmechanism 620 reciprocally moves the stirring vane 619 in directionsparallel to the substrate W. The stirring vane 619 comprises a platehaving saw-toothed irregularities 619 a in the form of successivetriangular teeth on its one side facing the substrate W. The platingtank 611 has a plating solution supply port 621 for supplying theplating solution into the plating tank 611 and a plating solutiondischarge port 622 for discharging the plating solution out of theplating tank 611.

In the present embodiment, when the stirring vane 619 with thesaw-toothed irregularities 619 a on its one side facing the substrate Wis reciprocally moved in directions parallel to the substrate W by thestirring mechanism 620, many swirls are produced uniformly and generallyin the plating solution. Thus, the flow of the plating solution that isin contact with the surface (to be plated) of the substrate W is moreuniformly and effectively applied to form a plated film having betterfilm thickness uniformity, i.e., a plated film having a more uniformfilm thickness, on the surface of the substrate W.

In the above embodiment, the saw-toothed irregularities 619 a in theform of successive triangular teeth are disposed on the side of thestirring vane 619 which faces the substrate W, as shown in FIG. 17A.However, the saw-toothed irregularities are not limited to those shownin FIG. 17A, but may be saw-toothed irregularities 619 b in the form ofsuccessive rectangular teeth as shown in FIG. 17B, or irregularities 619c in the form of a number of narrow grooves defined at predeterminedintervals as shown in FIG. 17C. Since the stirring vane 619 has, on oneside thereof, the saw-toothed irregularities 619 a in the form ofsuccessive triangular teeth, the saw-toothed irregularities 619 b in theform of successive rectangular teeth, or the irregularities 619 c in theform of a number of narrow grooves defined at predetermined intervals,the flow of the plating solution, which is caused by the reciprocatingmovement of the stirring vane 619, generates many swirls uniformly andgenerally in the plating solution. As the flow of the plating solutionthat is in contact with the substrate W is more uniformly andeffectively applied, it is possible to form a plated film having betterfilm thickness uniformity on the surface of the substrate W.

FIG. 18 shows a plating apparatus (electroplating apparatus) accordingto yet another embodiment of the present invention. Those parts of theplating apparatus shown in FIG. 18, which are denoted by referencecharacters identical to those shown in FIG. 17, are identical orcorrespond to those parts shown in FIG. 17. This principle applies toother figures. As shown in FIG. 18, the stirring mechanism 620 of theplating apparatus 610 has a plurality of (two in FIG. 18) stirring vanes619 each having saw-toothed irregularities 619 a on its one side facingthe substrate W. When the stirring vanes 619 of the stirring mechanism620 are reciprocally moved parallel to the substrate W, many swirls areproduced uniformly and generally in the plating solution. Thus, the flowof the plating solution that is in contact with the substrate W is moreuniformly and effectively applied to form a plated film having betterfilm thickness uniformity on the surface (surface to be plated) of thesubstrate W. Each of the stirring vanes 619 may have either one of theirregularities 619 a, 619 b and 619 c shown in FIGS. 17A through 17C.

FIG. 19A is a plan view of another stirring mechanism, and FIG. 19B is afront view of the other stirring mechanism. As shown in FIGS. 19A and19B, the stirring mechanism 620 has a plurality of (two in FIGS. 19A and19B) stirring vanes 619 that are actuatable by respective independentdrive mechanisms 623. Each of the drive mechanisms 623 comprises a drivemotor 623-1, a crank 623-2, a guide member 623-3, a drive shaft 623-4,and a bearing 623-5. The stirring vane 619 is mounted on the distal endof the drive shaft 623-4. As shown in FIG. 16, the stirring vanes 619extend substantially vertically from the upper portion toward the bottomof the plating tank 611.

When the drive motor 623-1 is energized to rotate as indicated by thearrow A, the crank 623-2, which has an end coupled to the drive shaft ofthe drive motor 623-1, has its other end reciprocally moved along aguide groove 623-3 a defined in the guide member 623-3. The drive shaft623-4, which is connected to the other end of the crank 623-2 andsupported by the bearing 623-5, is reciprocally moved as indicated bythe arrow B, thereby reciprocally moving the stirring vane 619 that ismounted on the distal end of the drive shaft 623-4.

As described above, the stirring mechanism 620 has the plural (two inFIGS. 19A and 19B) stirring vanes 619 that are actuatable by therespective independent drive mechanisms 623. When the stirring vanes 619are actuatable by the respective independent drive mechanisms 623, thestirring distribution of the plating solution can be adjusted to form aplated film having better film thickness uniformity on the surface (tobe plated) of the substrate W.

The stirring vanes 619 mounted on the drive mechanisms 623 of thestirring mechanism 620 shown in FIGS. 19A and 19B are identical in shapeto each other. However, the stirring vanes may have different shapes.Specifically, FIGS. 20A and 20B show a stirring mechanism havingvertically extending stirring vanes 624, 625 which are substantiallyequal in length to each other and have respective independent drivemechanisms 623. The stirring vanes 624, 625 have respective edges (tipends) 624 a, 625 a on one of their sides which are aligned with eachother to keep the stirring surfaces of the stirring vanes 624, 625 inalignment with each other, so that the stirring vanes 624, 625 can stirthe plating solution in vertically different regions. In other words,the distance between the stirring surfaces (tip ends) and the surface ofthe substrate W are the same. FIGS. 21A and 21B show a stirringmechanism having a longer stirring vane 632 and a shorter stirring vane634 that are disposed in upper and lower positions, respectively, andare reciprocally moved by respective independent drive mechanisms 623.The stirring vanes 632, 634 have respective edges 632 a, 634 a on theirone sides which are aligned with each other to keep the stirringsurfaces of the stirring vanes 632, 634 in alignment with each other, sothat the stirring vanes 632, 634 can stir the plating solution invertically different regions. By thus selectively using stirring vaneshaving different shapes, the stirring distribution of the platingsolution can be adjusted to form a plated film having better uniformityon the surface of the substrate W.

FIG. 22 shows still another stirring vane. As shown in FIG. 22, astirring vane 626 is mounted on a rotational shaft 627 which isangularly movable to change the angle of the stirring vane 626. As shownin FIGS. 23 and 24, for example, a plurality of (three as shown) suchstirring vanes 626 are mounted on a reciprocally movable drive mechanism(e.g., the drive mechanism 623 shown in FIGS. 19A and 19B). The stirringvanes 626 are reciprocally moved parallel to a surface (to be plated) Waof the substrate W as indicated by the arrow D shown in FIG. 23 or thearrow C shown in FIG. 24, and the rotational shafts 627 are angularlymoved as the direction in which the stirring vanes 626 are moved ischanged, thus changing the angle of the stirring vanes 626 with respectto the substrate W.

As described above, when the stirring vane 626 shown in FIG. 22 is usedas the stirring vanes of the stirring mechanism and the angle of thestirring vanes 626 with respect to the substrate W is changed as thedirection in which the stirring vanes 626 are moved is changed, as shownin FIGS. 23 and 24, a flow is caused in the plating solution asindicated by the arrow F shown in FIG. 23 or the arrow E shown in FIG.24. The flow of the plating solution thus produced by the motion of thestirring vanes 626 is generated uniformly and generally, applying theplating solution uniformly and effectively to the surface to be platedof the substrate W thereby to form a plated film having better filmthickness uniformity on the surface of the substrate W. In particular,since the plural stirring vanes 626 are employed, a flow of the platingsolution is produced more uniformly and generally near the surface Wa ofthe substrate W thereby to form a plated film of better film thicknessuniformity on the surface Wa of the substrate W.

FIG. 25 shows a plating apparatus (electroplating apparatus) accordingto yet another embodiment of the present invention. As shown in FIG. 25,the plating apparatus has two opposing stirring mechanisms 629, 230having respective stirring vanes 628 and disposed between a substrate Wand an anode 615 which are disposed opposing to each other in a platingtank 611. One of the stirring mechanisms 629 is disposed close to thesubstrate W, and the other stirring mechanism 630 is disposed close tothe anode 615. A flow of the plating solution which brings into contactwith both the substrate W and the anode 615 is more uniformly andeffectively applied by the stirring vane 628 (first stirring vane) ofthe stirring mechanism 629 and the stirring vane 628 (second stirringvane) of the stirring mechanism 630, for thereby forming a plated filmof better uniformity on the surface of the substrate W.

In the plating apparatus shown in FIG. 25, the stirring vanes 628, 628of the stirring mechanisms 629, 630 are free of irregularities on theirsides facing the substrate W and the anode 615. However, as shown inFIG. 26, stirring vanes 619 having saw-toothed irregularities 619 a inthe form of successive triangular teeth, as shown in FIG. 17A, on theirone sides facing the substrate W and the anode 615 may be mounted on thestirring mechanisms 629, 630. Alternatively, each of the stirring vanes619 may have saw-toothed irregularities 619 b in the form of successiverectangular teeth as shown in FIG. 17B, or irregularities 619 c in theform of a number of narrow grooves defined at predetermined intervals asshown in FIG. 17C.

In the plating apparatus shown in FIGS. 25 and 26, the stirringmechanisms 629, 630 may be reciprocally moved in unison with each otheror separately from each other, as indicated by the arrows G shown inFIG. 25.

Although embodiments of the present invention have been described above,the present invention is not limited to the above embodiments, butvarious changes and modifications may be made therein within the scopeof the technical concept described in the scope of the claims, and thespecification and drawings. Any configurations, structures, andmaterials which are not directly described in the specification anddrawings fall within the scope of the technical concept of the presentinvention insofar as they operate and offer the advantages according tothe present invention.

The present invention is concerned with a plating apparatus for platinga surface of a substrate, and more particularly with a plating apparatusfor use in forming a plated film in trenches, via holes, or resistopenings that are defined in a surface of a semiconductor wafer, andforming bumps to be electrically connected to electrodes of a package,on a surface of a semiconductor wafer.

1. An electroplating apparatus for plating a workpiece having a surfaceto be plated using a plating solution, the electroplating apparatuscomprising: a plating tank for holding the plating solution; an anodearranged in the plating tank so as to be immersed in the platingsolution held in the plating tank; a holder for holding the workpieceand bringing the surface of the workpiece into contact with the platingsolution held in the plating tank; a fixing plate having an openingtherein, the fixing plate being arranged so as to divide an interior ofthe plating tank into an anode compartment accommodating the anode and aworkpiece compartment accommodating the workpiece held by the holder;and a ring-shaped nozzle pipe fixed to the fixing plate in the platingtank so as to be immersed in the plating solution held in the platingtank, the nozzle pipe being shaped to extend along an outer profile ofthe workpiece, and having a plurality of injection nozzles for injectingthe plating solution toward the surface of the workpiece held by theholder to supply the plating solution into the plating tank.
 2. Anelectroplating apparatus according to claim 1, wherein the platingsolution is injected in streams from the injection nozzles, and whereinthe streams of the plating solution injected from the injection nozzlesintersect each other on or in front of a substantially central area ofthe surface of the workpiece held by the holder.
 3. An electroplatingapparatus according to claim 1, further comprising a plating solutioninjection nozzle for injecting the plating solution toward the anode tosupply the plating solution into the plating tank.
 4. An electroplatingapparatus according to claim 1, wherein the nozzle pipe is movablerelative to the workpiece held by the holder.
 5. An electroplatingapparatus according to claim 1, wherein the nozzle pipe and/or theinjection nozzles are made of an electrically insulating material.
 6. Aplating apparatus for plating a workpiece having a surface to be platedusing a plating solution, the plating apparatus comprising: a platingtank for holding a plating solution; and a stirring mechanism having aplurality of stirring vanes having stirring surfaces for immersing inthe plating solution in the plating tank and for stirring the platingsolution, wherein the plurality of stirring vanes extend verticallywithin the plating tank and are actuatable by respective independentdrive mechanisms each having an independent drive source, the pluralityof stirring vanes having respective tip ends which are aligned with eachother such that distances between the stirring surfaces of the stirringvanes and the surface of the substrate are equal.
 7. A plating apparatusaccording to claim 6, wherein stirring vanes of the plurality ofstirring vanes are different in shape from each other.
 8. A platingapparatus according to claim 6, wherein the plurality of stirring vanesare reciprocally movable in directions parallel to the surface of theworkpiece.
 9. A plating apparatus for plating a workpiece having asurface to be plated using a plating solution, the plating apparatuscomprising: a plating tank for holding a plating solution; and astirring mechanism having a stirring vane for immersing in the platingsolution in the plating tank and disposing in a position facing thesurface of the workpiece, the stirring vane being mounted on arotational shaft and reciprocally movable parallel to the surface of theworkpiece to stir the plating solution, wherein the stirring vane isoriented such that a plane of the stirring vane forms an angle withrespect to a plane perpendicular to the surface of the workpiece, thestirring mechanism being operable to vary the angle of the plane of thestirring vane with respect to the plane perpendicular to the surface ofthe workpiece as the stirring vane reciprocally moves by angularmovement of the rotational shaft about the longitudinal axis of therotational shaft.
 10. A plating apparatus according to claim 9, whereinthe stirring mechanism has a plurality of stirring vanes.
 11. Anelectroplating apparatus according to claim 1, wherein the injectionnozzles of the nozzle pipe are spaced apart along an annular axis of thenozzle pipe.
 12. An electroplating apparatus according to claim 1,further comprising a regulation plate having a central hole, theregulation plate being arranged in the plating tank between thering-shaped nozzle pipe and the workpiece held by the holder.
 13. Anelectroplating apparatus according to claim 1, further comprising astirring mechanism in the plating tank between the ring-shaped nozzlepipe and the substrate held by the holder, the stirring mechanism havinga stirring vane configured to move reciprocally parallel to the surfaceof the substrate for stirring the plating solution held in the platingtank.
 14. An electroplating apparatus according to claim 1, wherein theopening of the fixing plate has a size no larger than an inside diameterof the ring-shaped nozzle pipe.